We are currently having AC issues with our newly purchased 2015 Heartland Sundance 2880RLT fifth wheel. We purchased the unit in June and have been using the unit extensively since then. We are parked in a full sun lot most days. During the day we have had no problems with the AC keeping up with the summer heat and humidity. However at night we have been noticing that on relatively humid or not as hot nights (65-75 degrees) that the air will not kick on. We have the air set on 69 degrees every night. When we first got the unit, there no problems. We have begun to see an increase in waking up in the middle of the night warm and the air not running. I have checked the temp at the thermostat and it is 73 degrees generally but the air isn't on. I cycle the AC to off (that's how I checked the actual temp at the thermostat) and then to back to on again and it will kick on and go back to running. Then it will shut off after what I assume it has reached our desired sleeping temp of 69 degrees. We fall back asleep and then wake up hot again in the middle of the night to find it quit running and back to the actual temp at the thermostat of 73 degrees. So the cycle continues several times in the night. At no point in the night have we been noticing that the AC is running unless we cycle it off and then on again. The AC pumps out cool air and isn't freezing up. In the daytime, it works just fine. We bump up the temps inside the unit higher than 69 degrees so it doesn't work so hard to keep up. It doesn't do this every night either. Generally when the temps are moderate and it is humid. We have a 15000 BTU Dometic AC and a single zone Dometic thermostat. Anyone have any thoughts on what may be causing this? I don't really want to drive several hours to get warranty work done this early when we are using it pretty heavily this season but it is uncomfortable sleeping. We also have a small fan sitting on the dresser to circulate air. I've tried to scour the boards to see if anyone else had this issue and have found nothing for this.
Dometic thermostat issues
- Thread starter lynds876
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jimtoo
Moderator
Hi lynds876,
Welcome to the Heartland Owners Forum and to the family. We have a great bunch of folks here with lots of information and all willing to share their knowledge when needed.
I'm sure some of our other members will jump in with some info for you soon.
Be sure and check out our Heartland Owners Club. Join us at a rally when you can and meet lots of the great folks here and make friends for a lifetime.
Enjoy the forum and your new unit.
Jim M
Welcome to the Heartland Owners Forum and to the family. We have a great bunch of folks here with lots of information and all willing to share their knowledge when needed.
I'm sure some of our other members will jump in with some info for you soon.
Be sure and check out our Heartland Owners Club. Join us at a rally when you can and meet lots of the great folks here and make friends for a lifetime.
Enjoy the forum and your new unit.
Jim M
It has been fine generally in the day time and we checked once we arrived home today. It has been unseasonably cool today so we turned the thermostat down to 69 during the day and it adjusted to that temp from 73. And it kicked on again once the temps increased in the camper. I have no idea what it is doing at night.
Yes. The ambient temp is 73 when cycled off but the temp set on the thermostat is 69. Once you go back and put it on On again, then it will kick on and run again but won't kick back on once the temp climbs above 69 again after it has kicked off. It's bizarre. It only has been happening at night.
danemayer
Well-known member
Based on my past experience with Dometic, you've got an uphill battle to get them to send you a new thermostat without first letting an authorized Dometic servicer diagnose the problem. But it might be worth a call to ask them 1) if they will send you a thermostat for self-install and 2) if not, whether there's a nearby Dometic authorized servicer.
Garypowell
Well-known member
Not that I say our thermostat has the same problem but I do know it's operation has a great deal of swing to it. I think in home units they call this the "offset" or the amount the temperature is allowed to rise before it turns on the unit. I have not called Dometic but after taking the cover off there is no adjustment. I probably should call them to see if there is a sequence of buttons to press to make the offset smaller.
When this happens in our bedroom unit and we wake up.....we reach over and press it down a degree....don't even need to look. It always starts and usually that does it for the night.
Another trick is to put the fan on low (or high if you want) and then back on A/C.....you have to wait for the fan to kick on first in order for it to run continuously. This movement of air might help you be a little more comfortable. It also provides some noise to offset what is going on outside.
When this happens in our bedroom unit and we wake up.....we reach over and press it down a degree....don't even need to look. It always starts and usually that does it for the night.
Another trick is to put the fan on low (or high if you want) and then back on A/C.....you have to wait for the fan to kick on first in order for it to run continuously. This movement of air might help you be a little more comfortable. It also provides some noise to offset what is going on outside.
I've been keeping a close eye on the thermostat during the day and evening. We haven't had any problems with it since I reported it last week, however I did think because it was so muggy last night that we may have issues. We sure did. I had it set as we normally do at 69 degrees. I woke up hot again and when I turned it off, the actual temp was 73 again. I turned it back on thinking that it would solve the problem, but it never kicked back on again. I then turned it down a couple of degrees and cycled it off/on again thinking that may kick it on and it didn't happen. (I waited several minutes before trying these options). What finally did the trick was the turning off the fan from "auto" to "high" and then turning the thermostat down to 68. The AC turned on immediately and continued throughout the night. I did wake up one more time to what I thought was ice going through the main AC vent like it could freeze up, but I thought it may not since I had the fan on high. I bumped the thermostat back to 69 again and it worked fine the rest of the night. Do you all think that the thermostat would be correcting itself/AC not to freeze up at 69 degrees and not kicking on then if it is too muggy? I know that sounds too good to be true, but the thermostat works for the majority of the time. Only in the evenings when it is muggy does it seem to have a problem.
danemayer
Well-known member
I think there may be a temp sensor on the unit to detect ice buildup and shut it down to prevent damage. If it's really hot and muggy, that could be what's happening. If you have the Single Zone LCD thermostat, on AUTO, it will reduce fan speed when the ambient temp falls to less than 5 degrees above the set point. That could be leading to icing.
Another possible cause of icing is restricted return airflow which can be caused by dirt buildup on the filters.
Low freon can also cause icing.
Or some combination of factors.
Another possible cause of icing is restricted return airflow which can be caused by dirt buildup on the filters.
Low freon can also cause icing.
Or some combination of factors.
I've been having similar issues, but mine will shut down all through out the day.
High 90s to low 100s day time temps with heat index pushing 105 and higher in N.W. Louisiana aren't very enjoyable with a malfunctioning A.C.
I was looking to replace the thermostat, much cheaper than hauling the 3650 100 plus miles to have it checked out.
I found a replacement thermostat online and it had this notation below the description:
I did the reset a few hours ago and the unit hasn't shut off or short cycled since the reset. We'll see if it lasts.
Might give it a try and see if it "wakes up" your thermostat and control box.
Bob
High 90s to low 100s day time temps with heat index pushing 105 and higher in N.W. Louisiana aren't very enjoyable with a malfunctioning A.C.
I was looking to replace the thermostat, much cheaper than hauling the 3650 100 plus miles to have it checked out.
I found a replacement thermostat online and it had this notation below the description:
NOTE: If you install the thermostat and it still acts up, then perform a system initialization by following these steps:
Press and hold the '+' button.
Press and hold the 'On/Off Mode' button.
Hold both buttons down for about three seconds until the screen shows a -- --.
Release both buttons and press the 'On/Off Mode' button again to turn system off.
Press 'On/Off Mode' to turn back on. The thermostat has now been reset.
Press and hold the 'On/Off Mode' button.
Hold both buttons down for about three seconds until the screen shows a -- --.
Release both buttons and press the 'On/Off Mode' button again to turn system off.
Press 'On/Off Mode' to turn back on. The thermostat has now been reset.
I did the reset a few hours ago and the unit hasn't shut off or short cycled since the reset. We'll see if it lasts.
Might give it a try and see if it "wakes up" your thermostat and control box.
Bob
Thanks Bob! We will definitely try this as we have noticed it more and more not starting up. We had a pretty humid day yesterday here in IN and it would not kick on unless we cycled it to Off and then back to ON when we noticed it wasn't kicking on. We had it at 77 during the day and when we returned to the RV after a day out, the air wasn't on and it was 81 at the thermostat. We are cleaning and checking things out today to make sure we don't have another problem connected to it like low freon or a leaky duct.
We tried recycling or reinitializing the thermostat. That didn't solve our issue. It acted up that night. We finally removed the panel for the return duct and noticed that there was basically no difference in temperature between the vent blowing the cold air and the return. There was a flimsy piece separating the two that hadn't been sealed properly thus allowing a great deal of leaks. I'm hoping that the thermostat was doing a safety shutdown when our unit was freezing and when we noticed the ice pieces/condensation coming from the vents if we were to turn it on ON and high fan, that it was the unit thawing. My husband taped up the leaky return and we ran it on Auto at 69 degrees on the most humid night and it didn't shut down. I'm hoping that we have solved the issue and it wasn't a bad thermostat after all, just a safety precaution on the part of the thermostat and we weren't truly noticing the bigger issue.
